1. Technical Field
The present invention is related to an eddy current probe for surface inspection and an eddy current inspection device including the same.
2. Background Art
Not only is a gas turbine operated at the high temperature of 1300 degrees Celsius, frequent stoppage of motion during the peak season of summer, when power consumption is dramatically increased, causes surface defects to occur in its rotor due to thermal fatigue.
For a magnetic substance gas turbine, defects beyond a certain depth are difficult to be detected by a magnetic particle test because the current density is concentrated on the surface of the rotor due to the high magnetic permeability, and resolution is low for proximate defects, making it difficult to test and evaluate the surface defect of the rotor.
Accordingly, in the case of a magnetic substance rotor, the presence of defects is checked first through a magnetic particle test, and then if a defect is found, the size of the defect is evaluated through an ultrasonic test.
In addition, there have been demands for improvement in non-destructive inspection because harmful materials for humans and environment are generated due to the magnetic powder used in the magnetic particle test and the couplant used in the ultrasonic test.
The only known quantitative non-destructive inspection method for surface defect is the eddy current test (ECT). Accordingly, there is a strong demand for development and application of an eddy current probe that has excellent resolution and enhanced permeation depth in a magnetic substance.